Why Is Splitting Strategy for the Back Player Profitable ?

In appendix 19 of wizard homepage you give advice for ‘Splitting strategy for the back players’. Now, I believe in simulations but would as well like to know in words, why an edge can be achieved if the two players collude.

I am a Swiss advantage player who enjoys yearly vacations in Las Vegas. Primarily for WSOP poker tournaments in June, but as well for high limit blackjack as side action.

I come up with this topic, because I recently saw the back player strategy applied in one of the Swiss casinos, where playing together at the blackjack table is completely legal and as well tolerated.

Are there some simple explanations for the advantage by splitting almost any pair against high dealer upcard ?

mpower

Some splits don't give you an advantage they lessen your disadvantage.

Below is a very brief excerpt from a long-ago Post of the Month at bj21.com, which if you are a Green Chip member you can read at https://bj21.com/boards/green-chip-forums/sub_boards/green-chip-general/topics/splitting-hairs-on-hairy-splits

FB is the front bettor (or "caller"), who places the small wager, and BB is the big bettor (or "rider"), who places the big wager behind the FB.

******************************
As a simple example, let’s assume the FB bets $10, while the BB bets $100, on a 6D, S17, DAS game. Our heroes are dealt 6-6 vs. 9. What is their optimal play?

If we consult an expectation table, for example, the Wizard of Odds Appendix 9 table (sorry, Don… his were online so I didn’t have to type them myself!) at http://wizardofodds.com/games/blackjack/appendix/9/6ds17r4/, we can see that the Hit expectation is -0.347155, which means that if they Hit (the BS play, of course), our team can expect a return of -0.347155*($110) = -$38.18705.

But what if they Split? The same table shows the Split expectation is -0.602063, but this is for “normal” splits, where both resulting hands begin with the same wager. For each of the two hands, then, the expectation is one-half the given value, or -0.3010315. Now if the team performs an unequal split, they’ll have one $110 bet and one $10 bet, each with an expectation of -0.3010315. This means that our heroes can expect a return of -0.3010315*($110 + $10) = -$36.12378. Although this is still negative, it’s not as negative as the BS play of Hit. Thus, in this case the optimal “team” play is to perform an unequal split.
************************

The post then goes on to detail under what conditions such unequal splits should be used, depending on the house rules as well as the ratio of the big bet to the small bet. It then details how the information can be used for some Match Plays, and shows the maximum increase in player EV with the optimal strategy.

Spoiler alert: unless the BJ game has extremely liberal rules, the maximum return will not overcome the house edge.

The post is followed by 7 more that show the EV's for every potential split.

Dog Hand

Thanks DogHand.

Your answer enlightens my view on the topic. Unfortunately, I am no green chip member.

I have to add, that the mentioned Swiss Casino has excellent rules for 6 deck blackjack (with early surrender). The return must be around 100.21% for optimal play.

mpower

Quote: mpower

In appendix 19 of wizard homepage you give advice for ‘Splitting strategy for the back players’. Now, I believe in simulations but would as well like to know in words, why an edge can be achieved if the two players collude.

I am a Swiss advantage player who enjoys yearly vacations in Las Vegas. Primarily for WSOP poker tournaments in June, but as well for high limit blackjack as side action.

I come up with this topic, because I recently saw the back player strategy applied in one of the Swiss casinos, where playing together at the blackjack table is completely legal and as well tolerated.

Are there some simple explanations for the advantage by splitting almost any pair against high dealer upcard ?

mpower
link to original post

I think Wong’s book Blackjack secrets has charts in it with the strategy .

Quote: rainman

Some splits don't give you an advantage they lessen your disadvantage.
link to original post

There's a level beyond that too- some splits are profitable if you don't have to double your bet.

So you might have a pair of 3s vs. dealer 10, normally you wouldn't split those but if you have a tiny bet down and you have a backlining partner with a big bet, you can split them, and now your partner is drawing to a 3 rather than a 6 and with a chance to double.

I've played this way and it's worth something, but not a whole heck of a lot. Its biggest advantage might be being able to play a call-in game with a skilled player calling the shots and getting a little extra advantage by knowing backline split strategy. But I don't believe there are any casinos in the US that still allow it. They banned it because it creates disputes between the seated and backline player.

Quote: AutomaticMonkey

Quote: rainman

Some splits don't give you an advantage they lessen your disadvantage.
link to original post

There's a level beyond that too- some splits are profitable if you don't have to double your bet.

So you might have a pair of 3s vs. dealer 10, normally you wouldn't split those but if you have a tiny bet down and you have a backlining partner with a big bet, you can split them, and now your partner is drawing to a 3 rather than a 6 and with a chance to double.

I've played this way and it's worth something, but not a whole heck of a lot. Its biggest advantage might be being able to play a call-in game with a skilled player calling the shots and getting a little extra advantage by knowing backline split strategy. But I don't believe there are any casinos in the US that still allow it. They banned it because it creates disputes between the seated and backline player.
link to original post

The famous story goes something like this. The seated player is playing $5 bet the back betting player is betting $500 . They are dealt a hard 20 the seated player tells the back bettor that he’s going to hit the 20 unless the back bettor gives him $100 or some amount of money. The floor is called And says there’s nothing they can do as the seated player controls the spot. Has this ever happened, who knows maybe just a casino legend.

I’ve played everywhere but haven’t encountered this situation. If back better is allowed, the seated player always makes the decision and the back better must follow it.

Quote: aceside

I’ve played everywhere but haven’t encountered this situation. If back better is allowed, the seated player always makes the decision and the back better must follow it.
link to original post

Yes that is so. But one thing the back better doesn't ever have to do is put more money down. So if the seated better chooses to split, the back better can either put more money down for the split, or play his original bet on the first split hand only.

Those things are in online forums, not in real casinos. There are no such things as split for less or split for more, as far as I know.

Quote: aceside

Those things are in online forums, not in real casinos. There are no such things as split for less or split for more, as far as I know.
link to original post

I don't know of any place that allows it now either. But with 100% certainty, it was allowed in many stores up to the early 2000s.

This was back before there were a lot of casinos outside of Vegas and before they decided to make it all about slots, and blackjack tables were sometimes very, very busy.

Actually, one place allows back better, but only with a bet amount up to the seated player amount.

Quote: aceside

I’ve played everywhere but haven’t encountered this situation. If back better is allowed, the seated player always makes the decision and the back better must follow it.
link to original post

In some foreign countries whoever is betting more money controls the decision, if both betting the same the seated player does.

Quote: aceside

I’ve played everywhere but haven’t encountered this situation. If back better is allowed, the seated player always makes the decision and the back better must follow it.
link to original post

In some foreign countries whoever is betting more money controls the decision, if both betting the same the seated player does.
Also as Monkey previously said if the back bettor didn’t want to split he didn’t have to . The last time I have encountered this rule was around 2013

Quote: aceside

Actually, one place allows back better, but only with a bet amount up to the seated player amount.
link to original post

I believe we've seen photographs within the last 2 years of a casino with back-betting spots on the layout.

Details escape me at the moment, but I seem to recall something about New England - perhaps New Hampshire.

Quote: Dieter

Quote: aceside

Actually, one place allows back better, but only with a bet amount up to the seated player amount.
link to original post

I believe we've seen photographs within the last 2 years of a casino with back-betting spots on the layout.

Details escape me at the moment, but I seem to recall something about New England - perhaps New Hampshire.
link to original post

NH table games- those aren't exactly back betting circles. NH has a $50 max bet, but you can place up to 3 bets on a hand and that's how they get around it.

The place I think everyone is talking about is Foxwoods, and they allowed it up until 10+ years ago.

Quote: AutomaticMonkey

Quote: Dieter

Quote: aceside

Actually, one place allows back better, but only with a bet amount up to the seated player amount.
link to original post

I believe we've seen photographs within the last 2 years of a casino with back-betting spots on the layout.

Details escape me at the moment, but I seem to recall something about New England - perhaps New Hampshire.
link to original post

NH table games- those aren't exactly back betting circles. NH has a $50 max bet, but you can place up to 3 bets on a hand and that's how they get around it.

The place I think everyone is talking about is Foxwoods, and they allowed it up until 10+ years ago.
link to original post

Indeed. The NH photos I just looked up don't show what I remember, although many of the other details check.

In the UK back betting is commonplace. If the front bettor splits, the dealer will usually ask the back bettor/s if they want to pay to split as well. It doesn't draw any heat to say no and just pick one of the new hands for your existing bet to be linked to.

If that is the case, everybody wants to be a back better because there is an advantage there.

Only if the front bettor is following basic strategy. Or better yet, an amended strategy because they're trying to maximise the gains for their partner.

I would see it to believe it.

Quote: AutomaticMonkey

Quote: rainman

Some splits don't give you an advantage they lessen your disadvantage.
link to original post

There's a level beyond that too- some splits are profitable if you don't have to double your bet.

So you might have a pair of 3s vs. dealer 10, normally you wouldn't split those but if you have a tiny bet down and you have a backlining partner with a big bet, you can split them, and now your partner is drawing to a 3 rather than a 6 and with a chance to double.

I've played this way and it's worth something, but not a whole heck of a lot. Its biggest advantage might be being able to play a call-in game with a skilled player calling the shots and getting a little extra advantage by knowing backline split strategy. But I don't believe there are any casinos in the US that still allow it. They banned it because it creates disputes between the seated and backline player.
link to original post

AutomaticMonkey,

For an 8D game, this 3-3 vs. 10 unequal split should be made ONLY if R (the ratio of the big bet to the small bet) is more than 3.26 (if DAS is allowed) or more than 3.75 for NDAS. For 6D and DD games, these values change.

The OP mentioned Appendix 19. It took me awhile, but I finally found it:
https://wizardofodds.com/games/blackjack/splitting-strategy-back-betting/

The Wiz's strategy is based on infinite decks and does not consider the bet ratio R, which he says is a topic for future studies.

Hope this helps!

Dog Hand

I’m looking for a pair-splitting strategy when player can split and double up (only) the second split hand. The game is H-17, 6-deck and DAS. Please help!

Quote: aceside

I’m looking for a pair-splitting strategy when player can split and double up (only) the second split hand. The game is H-17, 6-deck and DAS. Please help!
link to original post

aceside,

I don't understand your question. What happens to the first split hand? What do you mean by "double up"?

Perhaps if you gave an example I could see what you mean.

Dog Hand

Here is an example of split-for-double: in the situation of player 8,8 vs 6, player bet one unit of free bet and then he splits the pair and bets one unit of real money bet on the second split hand. What is the strategy?

Here is another example of split-for-half: in the situation of player 2, 2 vs 3, player bet one unit of real money bet and then he splits the pair and bets one unit of free bet on the second split hand. What is the strategy now?

When should we split, if both the above split-for-double and split-for-half are allowed?

Quote: aceside

Here is an example of split-for-double: in the situation of player 8,8 vs 6, player bet one unit of free bet and then he splits the pair and bets one unit of real money bet on the second split hand. What is the strategy?

Here is another example of split-for-half: in the situation of player 2, 2 vs 3, player bet one unit of real money bet and then he splits the pair and bets one unit of free bet on the second split hand. What is the strategy now?

When should we split, if both the above split-for-double and split-for-half are allowed?
link to original post

aceside,

I don't mean to be obtuse, but what do you mean by "free bet"?

Dog Hand

A free bet is just a casino coupon that is confiscated by dealer whenever player uses it. If player wins, it’s still paid as a real money bet.

Quote: aceside

A free bet is just a casino coupon that is confiscated by dealer whenever player uses it. If player wins, it’s still paid as a real money bet.
link to original post

aceside,

Oh, ok... I thought you were talking about the blackjack variant.

If you have a $10 FB, it is worth roughly $5, but if you win you get $10. If you have any FB's, why would you play real money at all?

Leaving aside that question, in my reply to the original poster "mpower" I gave a link to a long-ago bj21 post. Part of that post discusses a topic closely related to your query about free bets:

Quote:

4. Applications to Match Plays

We can use this information for match play situations without the “back-betting” requirement. For example, say you have a $100 Match Play coupon, so you play it along with a $100 chip. Unfortunately, you’re dealt 7-7 vs. 8 in an 8D, H17, NDAS game. The first question to ask yourself is “Why am I playing such a crappy game?” Leaving that aside, the second and third questions are “What is the critical R for this situation? Should I split?” If you consult the table above, you’ll see that the critical R for this situation is 0.33. The answer to the last question, though, depends on whether or not you can “Split for Less”. In other words, if you split and the house rules allow you put out just a $100 chip for the split, you’d be “splitting for less”; if instead you have to put out $200, you’d be “splitting for more”.

Splitting for Less with Match Plays

In this situation, our original bet is roughly equivalent to a $150 bet, since the EV of a MP is roughly one-half of its face value (the actual value depends on several factors, including what whether or not you keep the coupon on a push). Thus, if we CAN split for just $100, then we’d be splitting for less. Note that this situation is equivalent to back-betting, where the FB wager is $100 about $150, and the BB wager is about $50 $100. We can just use the tables above for this case, looking for R* values less than 0.5 0.66. These R* < 0.5 0.66 values are all mostly against upcards of 7 & 8 with some against upcards of 2 & 3.

Splitting for More with Match Plays

Sometimes, the house rules require that, if you want to split with an original bet of a $100 MP and a $100 chip, you have to put out $200 in chips. This is equivalent to splitting for more, since your original wager was roughly $150, and your new wager will be $200. For this case, DON’T make any of the PU splits, but DO make all of the PE splits.

Note that I show a few corrections in the "Splitting for Less" section above by striking out the mistakes and bolding the corrections.

Here, PE (sPlit Equal) splits are the offensive +EV splits (like 9-9 vs. 6) and PU (sPlit Unequal) are the defensive -EV splits (like 6-6 vs. 9).

For your FB query, think of "real money bet, FB split" as "Splitting for Less", while "FB bet, real money split" as "Splitting for More", then follow the above advice.

Hope this helps!

Dog Hand

P.S. Answering your post caused me to review and correct what I wrote so many years ago... thanks!

Everything looks good to me except this part “PU (sPlit Unequal) are the defensive -EV splits (like 6-6 vs. 9).” I would say this hand decision of 6-6 vs. 9 is mostly a Hit, while 3-3 vs. 8 is a marginal Split that fits better into this example. I guess.

I don't see why using promo chips instead of real money would make any difference in strategy.

There are, for example, 10-10 vs. 6 should be split.

Quote: KevinAA

I don't see why using promo chips instead of real money would make any difference in strategy.
link to original post

All depends on the rules of the promo chips. If it's a thing where you can use it only once, you play it one way. If you play it until you lose it you play it differently, and keeping it or losing it on pushes adds yet another twist.

I used to get some where you could use them only on even money games, once it wins or loses you lose it but you got to play it again on a push. So I would play them at Pai Gow Poker where if I didn't have a two-headed monster of a hand, I would put all the power on the big hand looking for a push so I could play it again.